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		Removing the Redundant Value Classes
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            <h2 class="title" style="clear: both"><a id="removingredundantvalueclasses"></a>
		Removing the Redundant Value Classes
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      <p>
    The <code class="classname">PartData</code>, <code class="classname">SupplierData</code> and <code class="classname">ShipmentData</code>
	classes have been removed in this example, and the <code class="classname">Part</code>,
	<code class="classname">Supplier</code> and <code class="classname">Shipment</code> entity classes are used in
	their place.
</p>
      <p>
    The serial formats are created with the entity classes.
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      <a id="sentity_sampledatabase"></a>
      <pre class="programlisting">public class SampleDatabase
{
    ...
    public SampleDatabase(String homeDirectory)
        throws DatabaseException, FileNotFoundException
    {
        ...
        secConfig.setKeyCreator(new SupplierByCityKeyCreator(javaCatalog,
                                                     <strong class="userinput"><code>Supplier</code></strong>.class));
        ...
        secConfig.setKeyCreator(new ShipmentByPartKeyCreator(javaCatalog,
                                                     <strong class="userinput"><code>Shipment</code></strong>.class));
        ...
        secConfig.setKeyCreator(new 
                                ShipmentBySupplierKeyCreator(javaCatalog,
                                                     <strong class="userinput"><code>Shipment</code></strong>.class));
        ...
    }
} </pre>
      <p>
    The index key creator uses the entity class as well.
</p>
      <a id="sentity_supplierbycitykeycreator"></a>
      <pre class="programlisting">public class SampleDatabase
{
    ...

    private static class SupplierByCityKeyCreator
        extends TupleSerialKeyCreator
    {
        private SupplierByCityKeyCreator(ClassCatalog catalog,
                                         Class valueClass)
        {
            super(catalog, valueClass);
        }

        public boolean createSecondaryKey(TupleInput primaryKeyInput,
                                          Object valueInput,
                                          TupleOutput indexKeyOutput)
        {
            <strong class="userinput"><code>Supplier</code></strong> supplier = (<strong class="userinput"><code>Supplier</code></strong>) valueInput;
            String city = supplier.getCity();
            if (city != null) {
                indexKeyOutput.writeString(supplier.getCity());
                return true;
            } else {
                return false;
            }
        }
    }
} </pre>
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